The proposed research is aimed at elucidation of functions of the limbic system evaluated by comparison of effects of limbic system lesions on olfactory- and nonolfactory-cued behavior. The proposed research gets a priori plausibility from studies of comparative neuroanatomy which suggest that olfactory input will have special influence on the function of at least some limbic system structures. It is proposed to evaluate behavioral effects of lesions in various structures of the limbic system in terms of aspects of discrimination performance in a device in which olfactory and nonolfactory cues can be used in a comparable manner. Lesions will be produced by stereotactically guided electrolysis (or thin knife cuts where appropriate) and behavioral tests will be administered at least two weeks postoperatively to freely moving, unanesthetized animals (hooded rats).